Hi there. My name is Steve Lang. A few of you may know me from The Truth About Cars. Hopefully, that's a good thing.

My wife has kept a 2002 Toyota Prius for about a year and a half now. It received a new battery shortly before we bought it, and I'm more or less planning on keeping it for the forseeable future.

It has recieved OCI every 6k using Castrol Syntec and a Wix filter for the last 24k. Before that it was serviced at the Toyota dealership. I am looking at extending the OCI to 9k using a P1 filter and conventional oil, or a Mobil 1 filter / EP Oil every 15k.

These are the comments and the UOA results...

STEVE: 200,000 miles? Please! This engine's still a spring chicken. Metals look great here, so assuming she's still running well and you're not having any problems, then there's nothing about this sample that seems troublesome at all. Averages are based on about 7,600 miles on the oil. You could run your oil a bit longer, for sure. The TBN is kind of getting low (it's down to 1.4 and 1.0 or less is low), but the TBN tends to drop more slowly the more use an oil sees, so it might hang on at this level for a while. The viscosity was fine, assuming you used a 5W/20. Try 9K miles.